1. Field of the Invention
The present invention relates to pyridine-2,3-dicarboximides of the general formula I ##STR2## where
R.sup.1 is
hydrogen; PA1 C.sub.1 -C.sub.4 -alkoxy; PA1 C.sub.1 -C.sub.6 -alkyl which can carry one to three of the following groups: C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, C.sub.1 -C.sub.4 -dialkylamino, C.sub.3 -C.sub.8 -cycloalkyl, halogen, excluding C.sub.1 -C.sub.4 -dialkylaminoethyl if one of the radicals R.sup.2, R.sup.3 or R.sup.4 is amino or hydroxyl; PA1 C.sub.3 -C.sub.8 -cycloalkyl, which can carry one to three of the following groups: C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, halogen or nitro; PA1 C.sub.3 -C.sub.6 -alkenyl or C.sub.3 -C.sub.6 -alkynyl, which can be substituted up to three times by halogen, and PA1 at least one radical R.sup.2, R.sup.3 or R.sup.4 is nitro, a group OR.sup.5 or a group NR.sup.6 R.sup.7 and the other radicals R.sup.2, R.sup.3 and R.sup.4 are defined as follows: PA1 excluding .sup.6 -amino-5-cyano-4-phenylpyridine-2,3-dicarboximide; PA1 and their agriculturally utilizable salts. PA1 pyridine-2,3-dicarboxylic anhydrides of the formulae IIa and IIc ##STR3## where at least one of the radicals R.sup.2, R.sup.3 or R.sup.4 is nitro or NR.sup.6 R.sup.7, and the other radicals have the meanings mentioned at the outset for the final products I. PA1 Va: R.sup.4 is a nitro group and the radicals R.sup.2 and R.sup.3 have the meanings mentioned at the outset, as for the final product I; PA1 Vb: R.sup.3 is a nitro group and the radicals R.sup.2 and R.sup.4 have the meanings mentioned at the outset, as for the final product I, with the proviso that R.sup.2 is not methyl, halogen or amino (NH.sub.2) if R.sup.4 is hydrogen; PA1 Vc: R.sup.2 is a nitro group and the radicals R.sup.3 and R.sup.4 have the meanings mentioned at the outset, as for the final product I; PA1 Vd: the radicals R.sup.2, R.sup.3 and/or R.sup.4 are a group NR.sup.6 R.sup.7 and the other radicals R.sup.2, R.sup.3 or R.sup.4 have the meanings mentioned at the outset, as for the final product I, excluding diethyl and dimethyl 5-amino-6-methylpyridine-2,3-dicarboxylate, dimethyl 4-aminopyridine-2,3-dicarboxylate, diethyl 5,6-diaminopyridine-2,3-dicarboxylate, diethyl 6-amino-5-nitropyridine-2,3-dicarboxylate, diethyl 5-acetamido-6-methylpyridine-2,3-dicarboxylate, diethyl 5-methylamino-6-methylpyridine-2,3-dicarboxylate, diethyl 4-diethylamino-5-methylpyridine-2,3-dicarboxylate and diethyl 6-diethylamino-5-methylpyridine-2,3-dicarboxylate. PA1 hydrogen; PA1 C.sub.1 -C.sub.4 -alkoxy such as methoxy, ethoxy, propoxy, 1-methylethoxy, butoxy, 1-methylpropoxy, 2-methylpropoxy and 1,1-dimethylethoxy, in particular methoxy, ethoxy, 1-methylethoxy and 1,1-dimethylethoxy; PA1 C.sub.1 -C.sub.6 -alkyl such as methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl and 1-ethyl-2-methylpropyl, in particular propyl, 1-methylethyl and 1,1-dimethylethyl, the radicals mentioned being able to carry one to three of the following groups: PA1 R.sup.2, R.sup.3 and R.sup.4 at least one of the radicals is nitro, an OR.sup.5 or NR.sup.6 R.sup.7 group and the other radicals are: PA1 hydrogen, C.sub.1 -C.sub.4 -alkylcarbonyl, C.sub.1 -C.sub.4 -haloalkylcarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxy-C.sub.2 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkylcarbamoyl, C.sub.1 -C.sub.4 -dialkylcarbamoyl, C.sub.1 -C.sub.4 -alkylsulfonyl, C.sub.1 -C.sub.4 -haloalkylsulfonyl, sulfamoyl, C.sub.1 -C.sub.4 -alkylaminosulfonyl, C.sub.1 -C.sub.4 -dialkylaminosulfonyl, phenylsulfonyl, which can be mono- to trisubstituted by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, halogen, cyano or nitro, the alkyl, alkyloxy, haloalkyl, alkylthio and alkylamino constituents in the individual radicals contained in the definitions corresponding to those indicated above in the individual definitions listed; PA1 hydrogen, C.sub.1 -C.sub.4 -alkyl, in particular methyl and ethyl, benzyl, C.sub.1 -C.sub.4 -alkoxy, eg. methoxy and ethoxy, or together with R.sup.7 C.dbd.S; PA1 C.sub.1 -C.sub.4 -alkyl, in particular methyl and ethyl, and the radicals listed for R.sup.5.
i) hydrogen; PA2 ii) halogen, nitro or cyano; PA2 iii) C.sub.1 -C.sub.6 -alkyl, which can be substituted by one to five halogen atoms and/or one or two of the following radicals: PA2 iv) benzyl which can be substitute d up to three times by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalakyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, halogen, cyano or nitro; PA2 v) C.sub.3 -C.sub.8 -cycloalkyl which can be substituted one to three times by C.sub.1 -C.sub.4 -alkyl or halogen; PA2 vi) C.sub.2 -C.sub.6 -alkenyl which can be substituted up to three times by halogen and/or once by C.sub.1 -C.sub.3 -alkoxy or by phenyl which can carry one to three of the following groups: C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, halogen, cyano or nitro; PA2 vii) C.sub.2 -C.sub.6 -alkynyl which can be substituted up to three times by halogen or C.sub.1 -C.sub.3 -alkoxy and/or once by phenyl which can carry one to three of the following groups: C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, halogen, cyano or nitro; PA2 viii) C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -haloalkylthio, C.sub.2 -C.sub.5 -alkenyloxy, C.sub.2 -C.sub.5 -alkynyloxy, C.sub.1 -C.sub.4 -alkylsulfinyl, C.sub.1 -C.sub.4 -alkylsulfonyl, C.sub.1 -C.sub.4 -haloalkylsulfonyl; PA2 ix) phenoxy or phenylthio which can be substituted up to three times by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl , C.sub.1 -C.sub.4 -alkoxy , C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, halogen, cyano or nitro; PA2 x) a 5- or 6-membered heterocyclic radical having one or two heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen which can carry one or two of the following groups: C.sub.1 -C.sub.3 -alkyl, halogen, C.sub.1 -C.sub.3 -alkoxy or C.sub.2 -C.sub.4 -alkoxycarbonyl; PA2 xi) phenyl which can carry one to three of the following groups: PA2 xii) a group OR.sup.5, where R.sup.5 is hydrogen, C.sub.1 -C.sub.4 -alkylcarbonyl, C.sub.1 -C.sub.4 -haloalkylcarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxy-C.sub.2 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkylcarbamoyl, C.sub.1 -C.sub.4 -dialkylcarbamoyl, C.sub.1 -C.sub.4 -alkylsulfonyl, C.sub.1 -C.sub.4 -haloalkylsulfonyl, sulfamoyl, C.sub.1 -C.sub.4 -alkylaminosulfonyl, C.sub.1 -C.sub.4 -dialkylaminosulfonyl, phenylsulfonyl, which can be substituted one to three times by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, halogen, cyano or nitro; PA2 xiii) a group NR.sup.6 R.sup.7, where R.sup.6 is hydrogen, C.sub.1 -C.sub.4 -alkyl, benzyl, C.sub.1 -C.sub.4 -alkoxy or, together with R.sup.7, is C.dbd.S and R.sup.7 is hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkylcarbonyl, C.sub.1 -C.sub.4 -haloalkylcarbonyl, C.sub.1 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkoxy-C.sub.2 -C.sub.4 -alkoxycarbonyl, C.sub.1 -C.sub.4 -alkylcarbamoyl, C.sub.1 -C.sub.4 -dialkylcarbamoyl, C.sub.1 -C.sub.4 -alkylsulfonyl, C.sub.1 -C.sub.4 -haloalkylsulfonyl, sulfamoyl, C.sub.1 -C.sub.4 -alkylaminosulfonyl, C.sub.1 -C.sub.4 -dialkylaminosulfonyl, phenylsulfonyl, which can be substituted one to three times by C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, halogen, cyano or nitro; PA2 C.sub.1 -C.sub.4 -alkoxy as mentioned above, in particular methoxy and ethoxy; PA2 C.sub.1 -C.sub.4 -haloalkoxy such as difluoromethoxy, trifluoromethoxy, chlorodifluoromethoxy, dichlorofluoromethoxy, 1-fluoroethoxy, 2-fluoroethoxy, 2,2-difluoroethoxy, 1,1,2,2-tetrafluoroethoxy, 2,2,2-trifluoroethoxy, 2-chloro-1,1,2-trifluoroethoxy and pentafluoroethoxy, in particular trifluoromethoxy and pentafluoroethoxy; PA2 C.sub.1 -C.sub.4 -alkylthio such as methylthio, ethylthio, propylthio, 1-methylethylthio, n-butylthio, 1-methylpropylthio, 2-methylpropylthio and 1,1-dimethylethylthio, in particular methylthio and ethylthio; PA2 C.sub.1 -C.sub.4 -haloalkylthio such as difluoromethylthio, trifluoromethylthio, chlorodifluoromethylthio, 1-fluoroethylthio, 2-fluoroethylthio, 2,2-difluoroethylthio, 2,2,2-trifluoroethylthio, 2-chloro-2,2-difluoroethylthio, 2,2-dichloro-2-fluoroethylthio, 2,2,2-trichloroethylthio and pentafluoroethylthio, in particular trifluoromethylthio and pentafluoroethylthio; PA2 (C.sub.1 -C.sub.4 -dialkyl)amino such as dimethylamino, diethylamino, dipropylamino, diisopropylamino, dibutylamino, methylethylamino, in particular dimethylamino and methylethylamino; PA2 C.sub.3 -C.sub.8 -cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl, in particular cyclopropyl, cyclopentyl and cyclohexyl; PA2 halogen such as fluorine, chlorine, bromine, iodine, in particular fluorine and chlorine; PA2 additionally C.sub.3 -C.sub.8 -cycloalkyl as mentioned above, in particular cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl, which can carry one to three of the following groups: C.sub.1 -C.sub.6 -alkyl as mentioned above, in particular methyl, ethyl and isopropyl; haloalkyl as mentioned above for the homologous haloalkylthio radicals, in particular trifluoromethyl; C.sub.1 -C.sub.4 -alkoxy as mentioned above, in particular methoxy and ethoxy; C.sub.1 -C.sub.4 -haloalkoxy as mentioned above, in particular trifluoromethoxy; halogen as mentioned above, in particular fluorine and chlorine; PA2 C.sub.3 -C.sub.6 -alkenyl such as 2-propenyl, 2-methylethenyl, 2-butenyl, 3-butenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 3-methyl-2-butenyl, 1-methyl-2-butenyl, 2-methyl-2-butenyl, 1-methyl-3-butenyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1,2-dimethyl-2-propenyl, 1-ethyl-2-propenyl, 1-, 2-, 3-, 4- or 5-hexenyl, 1-methyl-2-pentenyl, 2-methyl-2-pentenyl, 3-methyl-2-pentenyl, 4-methyl-2-pentenyl, 1-methyl-3-pentenyl, 2-methyl-3-pentenyl, 3-methyl-3-pentenyl, 4-methyl-3-pentenyl, 1-methyl-4-pentenyl, 2-methyl-4-pentenyl, 3-methyl-4-pentenyl, 4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1-dimethyl-3-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl, 2,2-dimethyl-3-butenyl, 2,3-dimethyl-2-butenyl, 2,3-dimethyl-3-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl, 1,1,2-trimethyl-2-propenyl, 1-ethyl-1-methyl-2-pentenyl and ethyl-2-methyl-2-pentenyl, in particular ethenyl, 2-propenyl, 1-methylethenyl, 2-butenyl, 3-butenyl, 1-methylpropyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, which can be mono- to trisubstituted by halogen, in particular fluorine and chlorine; PA2 additionally C.sub.3 -C.sub.6 -alkynyl such as propargyl, 2-butynyl, 3-butynyl, 1-methyl-2-propynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, 1-methyl-3-butynyl, 2-methyl-3-butynyl, 1-methyl-2-butynyl, 3-methyl-1-butynyl, 1,1-dimethyl-2-propynyl, 1-ethyl-2-propynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, 5-hexynyl, 1-methyl-2-pentynyl, 1-methyl-3-pentynyl, 1-methyl-4-pentynyl, 3-methyl-4-pentynyl, 4-methyl-2-pentynyl, 1,1-dimethyl-2-butynyl, 1,1-dimethyl-3-butynyl, 1,2-dimethyl-3-butynyl, 2,2-dimethyl-3-butynyl, 1-ethyl-2-butynyl, 1-ethyl-3-butynyl, 2-ethyl-3-butynyl and 1-ethyl-1-methyl-2-propynyl, in particular 1-methyl-2-propynyl and 1,1-dimethyl-2-propynyl, which can be mono- to trisubstituted by halogen as mentioned above, in particular fluorine and chlorine, and/or monosubstituted by phenyl; PA2 hydrogen, halogen as mentioned under R.sup.1, in particular fluorine and chlorine; cyano; C.sub.1 -C.sub.6 -alkyl as mentioned under R.sup.1, in particular methyl, ethyl, propyl, 1-methylethyl and 1,1-dimethylethyl, which can carry one to five halogen atoms, as mentioned under R.sup.1, in particular fluorine and chlorine, and/or one or two of the following radicals: C.sub.1 -C.sub.4 -alkoxy as mentioned under R.sup.1, in particular methoxy, ethoxy, 1-methylethoxy and 1,1-dimethylethoxy; C.sub.1 -C.sub.4 -haloalkoxy as mentioned under R.sup.1, in particular halomethoxy such as difluoromethoxy and trifluoromethoxy; C.sub.1 -C.sub.4 -alkylthio as mentioned under R.sup.1, in particular methylthio and ethylthio; C.sub.1 -C.sub.4 -haloalkylthio, as mentioned under R.sup.1, in particular difluoromethylthio and trifluoromethylthio; PA2 C.sub.3 -C.sub.6 -cycloalkyl as mentioned under R.sup.1, in particular cyclopropyl; PA2 additionally benzyl, which can be mono- to trisubstituted by C.sub.1 -C.sub.4 -alkyl as mentioned under R.sup.1, in particular methyl, ethyl and 1-methylethyl; C.sub.1 -C.sub.4 -haloalkyl as mentioned under R.sup.1, in particular trifluoromethyl and chlorodifluoromethyl; C.sub.1 -C.sub.4 -alkoxy as mentioned under R.sup.1, in particular methoxy and ethoxy; C.sub.1 -C.sub.4 -haloalkoxy as mentioned under R.sup.1, in particular trifluoromethoxy, trichloromethoxy and pentafluoroethoxy; C.sub.1 -C.sub.4 -alkylthio as mentioned under R.sup.1, in particular methylthio and ethylthio; C.sub.1 -C.sub.4 -haloalkylthio as mentioned under R.sup.1, in particular difluoromethylthio, trifluoromethylthio and pentafluoromethylthio; halogen, in particular fluorine and chlorine; cyano or nitro; PA2 additionally C.sub.3 -C.sub.8 -cycloalkyl, as mentioned under R.sup.1, in particular cyclopropyl, cyclopentyl and cyclohexyl; which can be mono- to trisubstituted by C.sub.1 -C.sub.4 -alkyl as mentioned under R.sup.1, in particular methyl and ethyl; or halogen as mentioned under R.sup.1, in particular fluorine and chlorine; PA2 C.sub.2 -C.sub.6 -alkenyl as mentioned under R.sup.1, additionally 1-ethenyl, 1-propenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-pentenyl, 1-methyl-l-butenyl, 2-methyl-1-butenyl, 1-ethyl-1-propenyl, 1-methyl-1-pentenyl, .sup.2 -methyl-1-pentenyl, .sup.3 -methyl-1-pentenyl, 4-methyl-1-pentenyl, 1,2-dimethyl-1-butenyl, 1,3-dimethyl-1-butenyl, 2,3-dimethyl-1-butenyl, 3,3-dimethyl-1-butenyl, ethyl-1-butenyl, .sup.2 -ethyl-1-butenyl, 1-ethyl-2-methyl-1-pentenyl, in particular ethenyl, 1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methylpropenyl, 1-methyl-2-propenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, which can be mono- to trisubstituted by halogen as mentioned under R.sup.1, in particular fluorine and chlorine; or C.sub.1 -C.sub.3 -alkoxy as mentioned under R.sup.1, in particular methoxy and ethoxy; and/or monosubstituted by phenyl, the phenyl radical in turn being able to carry one to three of the following groups: alkyl as mentioned under R.sup.1, in particular methyl, ethyl and 1-methylethyl; haloalkyl as mentioned under R.sup.1, in particular trifluoromethyl and chlorodifluoromethyl; alkoxy as mentioned under R.sup.1, in particular methoxy and ethoxy; haloalkoxy as mentioned under R.sup.1, in particular trifluoromethoxy, trichloromethoxy and pentafluoroethoxy; alkylthio as mentioned under R.sup.1, in particular methylthio and ethylthio; haloalkylthio as mentioned under R.sup.1, in particular difluoromethylthio, trifluoromethylthio and pentafluoromethylthio; halogen as mentioned under R.sup.1, in particular fluorine and chlorine; cyano or nitro; PA2 C.sub.2 -C.sub.6 -alkynyl, as mentioned under R.sup.1, in addition ethynyl, 1-propynyl, 1-butynyl, 1-pentynyl, 1-hexynyl, 3-methyl-1-pentynyl, 4-methyl-1-pentynyl, in particular ethynyl, 1-propynyl and propargyl, which can be mono- to trisubstituted by halogen as mentioned above, in particular fluorine and chlorine; or alkoxy as mentioned above, in particular methoxy and ethoxy; and/or monosubstituted by phenyl, the phenyl radical in turn being able to carry one to three of the following groups: alkyl as mentioned above, in particular methyl, ethyl and 1-methylethyl; haloalkyl as mentioned above, in particular trifluoromethyl and chlorodifluoromethyl; alkoxy as mentioned above, in particular methoxy and ethoxy; haloalkoxy as mentioned above, in particular trifluoromethoxy, trichloromethoxy and pentafluoroethoxy; alkylthio as mentioned above, in particular methylthio and ethylthio-; haloalkylthio as mentioned above, in particular difluoromethylthio, trifluoromethylthio and pentafluoromethylthio; halogen as mentioned above, in particular fluorine and chlorine; cyano or nitro; PA2 additionally C.sub.1 -C.sub.4 -alkoxy or -alkylthio as mentioned under R.sup.1, in particular methoxy and ethoxy, methylthio and ethylthio; PA2 C.sub.1 -C.sub.4 -haloalkoxy or -haloalkylthio as mentioned above, in particular trifluoromethoxy, trichloromethoxy and pentafluoroethoxy, difluoromethylthio, trifluoromethylthio and pentafluoroethylthio; PA2 C.sub.2 -C.sub.5 -alkenyloxy such as vinyloxy, 2-propenyloxy, 1-methylethenyloxy, 2-methyl-3-butenyloxy, in particular 2-propenyloxy and 2-methyl-3-butenyloxy; PA2 C.sub.2 -C.sub.5 -alkynyloxy such as ethynyloxy, 2-propynyloxy, 1-methylethynyloxy, 2-methyl-3-butynyloxy, in particular 2-propynyloxy and 2-methyl-3-butynyloxy; PA2 C.sub.1 -C.sub.4 -alkylsulfinyl such as methylsulfinyl, ethylsulfinyl, n-propylsulfinyl, i-propylsulfinyl, n-butylsulfinyl, tert-butylsulfinyl, in particular methylsulfinyl; PA2 C.sub.1 -C.sub.4 -alkylsulfonyl such as methylsulfonyl, ethylsulfonyl, n-propylsulfonyl, i-propylsulfonyl, n-butylsulfonyl, tert-butylsulfonyl, in particular methylsulfonyl; PA2 C.sub.1 -C.sub.4 -haloalkylsulfonyl such as trifluoromethylsulfonyl, pentafluoroethylsulfonyl, monofluorobutylsulfonyl, in particular trifluoromethylsulfonyl; PA2 phenoxy or phenylthio, which can be mono- to trisubstituted by C.sub.1 -C.sub.4 -alkyl as mentioned under R.sup.1, in particular methyl, ethyl and isopropyl; haloalkyl as mentioned under R.sup.1, in particular trifluoromethyl and chlorodifluoromethyl; alkoxy as mentioned above, in particular trifluoromethoxy, trichloromethoxy and pentafluoroethoxy; alkylthio as mentioned above, in particular methylthio and ethylthio; haloalkylthio as mentioned above, in particular difluoromethylthio, trifluoromethylthio and pentafluoromethylthio; halogen as mentioned above, in particular fluorine and chlorine; cyano or nitro; PA2 a 5- or 6-membered saturated or aromatic heterocyclic radical, containing one or two heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, such as tetrahydrofuryl, tetrahydropyranyl, furyl, thienyl, thiazolyl, pyrazolyl, pyrrolyl, pyridyl, morpholino, piperidino, pyrimidyl, for example 2-tetrahydrofuranyl, 3-tetrahydrofuranyl, 2-tetrahydrothienyl, 3-tetrahydrothienyl, 2-tetrahydropyranyl, 3-tetrahydropyranyl, 4-tetrahydropyranyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 2-pyrrolyl, 3-pyrrolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-pyridyl, 3-pyridyl and 4-pyridyl, which can carry one to three of the following substituents: C.sub.1 -C.sub.3 -alkyl as mentioned above, in particular methyl and ethyl, halogen as mentioned above, in particular fluorine and chlorine, C.sub.1 -C.sub.3 -alkoxy as mentioned under R.sup.1, in particular methoxy and ethoxy; or C.sub.1 -C.sub.4 -alkoxycarbonyl such as methoxycarbonyl and ethoxycarbonyl, in particular methoxycarbonyl; PA2 phenyl, which can carry one to three of the following groups: PA2 C.sub.1 -C.sub.6 -alkyl as mentioned under R.sup.1, in particular methyl, ethyl and isopropyl; C.sub.1 -C.sub.6 -haloalkyl as mentioned under R.sup.1, in particular trifluoromethyl and chlorodifluoromethyl; C.sub.1 -C.sub.6 -alkoxy as mentioned under R.sup.1, in particular methoxy and ethoxy; C.sub.1 -C.sub.6 -haloalkoxy as mentioned under R.sup.1, in particular trifluoromethoxy, trichaioromethoxy and pentafluoroethoxy; C.sub.1 -C.sub.6 -alkylthio as mentioned under R.sup.1, in particular methylthio and ethylthio; C.sub.1 -C.sub.6 haloalkylthio as mentioned under R.sup.1, in particular difluoromethylthio, trifluoromethylthio and pentafluoromethylthio; halogen as mentioned under R.sup.1, in particular fluorine and chlorine; cyano or nitro;
C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkoxy, C.sub.1 -C.sub.4 -alkylthio, C.sub.1 -C.sub.4 -haloalkylthio, C.sub.3 -C.sub.6 -cycloalkyl or cyano; PA3 C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -haloalkyl, C.sub.1 -C.sub.6 -alkoxy, C.sub.1 -C.sub.6 -haloalkoxy, C.sub.1 -C.sub.6 -alkylthio , C.sub.1 -C.sub.6 -haloalkylthio, halogen, nitro or cyano;
The invention furthermore relates to processes for preparing the compounds I and their use for controlling undesired plant growth, and novel pyridine-2,3-dicarboxylic acid esters and pyridine-2,3-dicarboxylic anhydrides, in particular nitro-substituted in each case, which are used as intermediates for preparing the compounds I.
2. Description of Related Art
N-substituted pyridinedicarboximides and their derivatives are known. EP-A 128 006 describes, inter alia, N-cycloalkylenepyridinedicarboximides and their use as soil fungicides.
U.S. Pat. No. 3,539,568 describes a process for preparing 2,3- and 3,4-pyridinedicarboximides and their reaction to give isomeric dicarboxamides which can be used as intermediates for herbicidal pyrimidinediones.
U.S. Pat. No. 4,261,730 describes 3-carboxypyridine-2-N-(aryl)carboxamides and phthalamic acids having growth-regulating action.
U.S. Pat. No. 4,658,030 discloses a process for preparing herbicidal 2-(imidazolin-2-yl)nicotinic acids based on 3-carboxypyridine-2-(N-2-carbamido-3-methyl-2-butyl)carboxamides.
Helv. Chim. Acta 1988, Vol. 71, pp. 486 and 493 discloses a cycloaddition process for preparing pyridine-2,3-dicarboximides.
J 5 7085-386 describes specifically substituted pyridine-2,3-dicarboximides having antitumor action. 6-Amino-5-cyano-4-phenylpyridinecarboximide is disclosed in CA 117, 150 849.
Herbicidally active pyridine-2,3-dicarboximides are disclosed in EP-A 422 456.
Intermediates from the pyridine-2,3-dicarboxylic acid diester group can only be taken from the prior art in isolated cases. Thus EP-A 227 932 describes pyridine-2,3-dicarboxylic acid diesters having the following substitution pattern in the 5/6 position: CH.sub.3 /NO.sub.2, NH.sub.2 /NH.sub.2, NO.sub.2 /Cl and NO.sub.2 /NH.sub.2. Dimethyl 4-aminopyridine-2,3-dicarboxylate is known from Chemical Abstracts 111, 112292p (1989), dimethyl or diethyl 5-amino-6-methylpyridine-2,3-dicarboxylate from Beilstein No. 4-22-006875 (Jones, Am. Soc. 74 (1972), p. 1489). Diethyl 5-acetamido- and 5-methylamino-6-methylpyridine-2,3-dicarboxylates are published in EP-A 322 616. 4-Diethylamino-5-methyl- and 5-diethylamino-4-methylpyridine are described in Chemical Abstracts 81, 169499c (1974) and 79, 31999t (1973).